Articulate wrist with flexible central member having stiffening members

ABSTRACT

An articulable wrist for an end effector includes a distal linkage provided at a distal end of the articulable wrist, a proximal linkage provided at a proximal end of the articulable wrist, a central channel cooperatively defined at least in part by the distal and proximal linkages and extending between the distal and proximal ends, and flexible member arranged within the central channel and providing one or more lobes arranged about a periphery of the flexible member. One or more stiffening members are arranged within the flexible member and extending at least partially between the distal and proximal ends, wherein at least one of the one or more stiffening members is positioned within a corresponding one of the one or more lobes.

BACKGROUND

Minimally invasive surgical (MIS) instruments are often preferred overtraditional open surgical devices due to reduced post-operative recoverytime and minimal scarring. Laparoscopic surgery is one type of MISprocedure in which one or more small incisions are formed in the abdomenof a patient and a trocar is inserted through the incision to form apathway that provides access to the abdominal cavity. Through thetrocar, a variety of instruments and surgical tools can be introducedinto the abdominal cavity. The instruments and tools introduced into theabdominal cavity via the trocar can be used to engage and/or treattissue in a number of ways to achieve a diagnostic or therapeuticeffect.

Various robotic systems have recently been developed to assist in MISprocedures. Robotic systems can allow for more instinctive handmovements by maintaining natural eye-hand axis. Robotic systems can alsoallow for more degrees of freedom in movement by including anarticulable “wrist” joint that creates a more natural hand-likearticulation. In such systems, an end effector positioned at the distalend of the instrument can be articulated (moved) using a cable drivenmotion system having one or more drive cables (or other elongatemembers) that extend through the wrist joint. A user (e.g., a surgeon)is able to remotely operate the end effector by grasping andmanipulating in space one or more controllers that communicate with atool driver coupled to the surgical instrument. User inputs areprocessed by a computer system incorporated into the robotic surgicalsystem, and the tool driver responds by actuating the cable drivenmotion system and thereby actively controlling the tension balance inthe drive cables. Moving the drive cables articulates the end effectorto desired angular positions and configurations.

Joint stiffness at the wrist is required to resist external loads andmoments induced by end effector actuation. To maintain stiffness in thewrist joint in a static condition and equally during use, the drivecables are typically pretensioned by applying torque to thecorresponding drive inputs. The application and maintenance of drivecable pretension places reaction forces and resulting stress on all thetool components in the load path. The magnitude of the pretension force,however, will tend to degrade over time due to creep of the drive cablesand related plastic components, and decreased pretension willcorrespondingly lower the wrist joint stiffness. Low wrist jointstiffness can result in inaccurate tool tip positioning, excesscompliance when encountering external or tissue loads, and “tip dive” orunexpected tip deflection when clamp loads are applied at the endeffector.

BRIEF DESCRIPTION OF THE DRAWINGS

The following figures are included to illustrate certain aspects of thepresent disclosure, and should not be viewed as exclusive embodiments.The subject matter disclosed is capable of considerable modifications,alterations, combinations, and equivalents in form and function, withoutdeparting from the scope of this disclosure.

FIG. 1 is a block diagram of an example robotic surgical system that mayincorporate some or all of the principles of the present disclosure.

FIG. 2 is an isometric side view of an example surgical tool that mayincorporate some or all of the principles of the present disclosure.

FIG. 3 illustrates potential degrees of freedom in which the wrist ofthe surgical tool of FIG. 2 may be able to articulate (pivot) ortranslate.

FIG. 4 is an enlarged isometric view of the distal end of the surgicaltool of FIG. 2.

FIG. 5 is an isometric side view of the end effector of FIG. 4 in anopen position, according to one or more embodiments.

FIGS. 6A and 6B are enlarged isometric front and back views,respectively, of the wrist of FIGS. 4 and 5, according to one or moreembodiments.

FIGS. 7A and 7B are isometric and exploded views, respectively, of theflexible member and the distal and proximal adapters of FIGS. 6A-6B,according to one or more embodiments.

FIGS. 8A and 8B are isometric and end views, respectively, of oneexample embodiment of the flexible member of FIGS. 6A-6B in accordancewith the principles of the present disclosure.

FIGS. 9A and 9B are isometric and end views, respectively, of anotherexample embodiment of the flexible member of FIGS. 6A-6B in accordancewith the principles of the present disclosure.

FIGS. 10A and 10B are isometric and end views, respectively, of anotherexample embodiment of the flexible member of FIGS. 6A-6B in accordancewith the principles of the present disclosure.

FIGS. 11A and 11B are isometric and end views, respectively, of anotherexample embodiment of the flexible member of FIGS. 6A-6B in accordancewith the principles of the present disclosure.

DETAILED DESCRIPTION

The present disclosure is related to robotic surgical systems and, moreparticularly, to end effectors with articulable wrists that include aflexible member extending through the articulable wrists and one or morestiffening members used to resist bending of the flexible member and,thus, the articulable wrist.

Embodiments described herein disclose an articulable wrist for an endeffector of a surgical tool. The articulable wrist includes a distallinkage provided at a distal end of the articulable wrist, a proximallinkage provided at a proximal end of the articulable wrist, and acentral channel cooperatively defined by the distal and proximallinkages and extending between the distal and proximal ends. A flexiblemember may be arranged within the central channel and has a first endoperatively coupled to the distal linkage and a second end axiallymovable relative to the proximal linkage. One or more stiffening membersmay be arranged within the flexible member and extend at least partiallybetween the first and second ends. The stiffening members may increase astiffness of the flexible member and the articulable wrist againstbending.

The stiffening elements are not in tension and their stiffness isgoverned by inherent material properties and the moment of inertia ofthe elements in bending. As will be appreciated, these properties willremain constant through shelf life. The diameter, material type, andlengths of the stiffening members can be tailored to individuallysupport unique pitch and yaw angles, and can counter the effect ofoff-center bending moments now encountered by high cable loading duringclamping. In some embodiments, the flexible member may be extruded withthe stiffening rods embedded in the extruded matrix, or may otherwise bepost assembled and adhesively bonded.

FIG. 1 is a block diagram of an example robotic surgical system 100 thatmay incorporate some or all of the principles of the present disclosure.As illustrated, the system 100 can include at least one set of userinput controllers 102 a and at least one control computer 104. Thecontrol computer 104 may be mechanically and/or electrically coupled toa robotic manipulator and, more particularly, to one or more roboticarms 106 (alternately referred to as “tool drivers”). In someembodiments, the robotic manipulator may be included in or otherwisemounted to an arm cart capable of making the system portable. Eachrobotic arm 106 may include and otherwise provide a location formounting one or more surgical instruments or tools 108 for performingvarious surgical tasks on a patient 110. Operation of the robotic arms106 and associated tools 108 may be directed by a clinician 112 a (e.g.,a surgeon) from the user input controller 102 a.

In some embodiments, a second set of user input controllers 102 b (shownin dashed lines) may be operated by a second clinician 112 b to directoperation of the robotic arms 106 and tools 108 in conjunction with thefirst clinician 112 a. In such embodiments, for example, each clinician112 a,b may control different robotic arms 106 or, in some cases,complete control of the robotic arms 106 may be passed between theclinicians 112 a,b. In some embodiments, additional robotic manipulators(not shown) having additional robotic arms (not shown) may be utilizedduring surgery on the patient 110, and these additional robotic arms maybe controlled by one or more of the user input controllers 102 a,b.

The control computer 104 and the user input controllers 102 a,b may bein communication with one another via a communications link 114, whichmay be any type of wired or wireless telecommunications means configuredto carry a variety of communication signals (e.g., electrical, optical,infrared, etc.) and according to any communications protocol.

The user input controllers 102 a,b generally include one or morephysical controllers that can be grasped by the clinician 112 a,b andmanipulated in space while viewing the procedure via a stereo display.The physical controllers generally comprise manual input devices movablein multiple degrees of freedom, and often include an actuatable handleor pedal for actuating the surgical tool(s) 108. The control computer104 can also include an optional feedback meter viewable by theclinician 112 a,b via a display to provide a visual indication ofvarious surgical instrument metrics, such as the amount of force beingapplied to the surgical instrument (i.e., a cutting instrument ordynamic clamping member).

FIG. 2 is an isometric side view of an example surgical tool 200 thatmay incorporate some or all of the principles of the present disclosure.The surgical tool 200 may be the same as or similar to the surgicaltool(s) 108 of FIG. 1 and, therefore, may be used in conjunction with arobotic surgical system, such as the robotic surgical system 100 ofFIG. 1. In other embodiments, however, aspects of the surgical tool 200may be adapted for use in a manual or hand-operated manner, withoutdeparting from the scope of the disclosure.

As illustrated, the surgical tool 200 includes an elongated shaft 202,an end effector 204, a wrist 206 (alternately referred to as a “wristjoint” or an “articulable wrist joint”) that couples the end effector204 to the distal end of the shaft 202, and a drive housing 208 coupledto the proximal end of the shaft 202. In robotic surgical systems, thedrive housing 208 can include coupling features that releasably couplethe surgical tool 200 to the robotic surgical system (e.g., the roboticarm 106 of FIG. 1).

The terms “proximal” and “distal” are defined herein relative to arobotic surgical system having an interface configured to mechanicallyand electrically couple the surgical tool 200 (e.g., the drive housing208) to a robotic manipulator. The term “proximal” refers to theposition of an element closer to the robotic manipulator and the term“distal” refers to the position of an element closer to the end effector204 and thus further away from the robotic manipulator. Alternatively,in manual or hand-operated applications, the terms “proximal” and“distal” are defined herein relative to a user, such as a surgeon orclinician. The term “proximal” refers to the position of an elementcloser to the user and the term “distal” refers to the position of anelement closer to the end effector 204 and thus further away from theuser. Moreover, the use of directional terms such as above, below,upper, lower, upward, downward, left, right, and the like are used inrelation to the illustrative embodiments as they are depicted in thefigures, the upward or upper direction being toward the top of thecorresponding figure and the downward or lower direction being towardthe bottom of the corresponding figure.

During use of the surgical tool 200, the end effector 204 is configuredto move (pivot) relative to the shaft 202 at the wrist 206 to positionthe end effector 204 at desired orientations and locations relative to asurgical site. To accomplish this, the drive housing 208 includes(contains) various drive inputs and mechanisms (e.g., gears, actuators,etc.) designed to control operation of various features associated withthe end effector 204 (e.g., clamping, firing, rotation, articulation,cutting, etc.). In at least some applications, the shaft 202, and hencethe end effector 204 coupled thereto, is configured to rotate about alongitudinal axis A₁ of the shaft 202. In such embodiments, at least oneof the drive inputs controls rotational movement of the shaft 202 aboutthe longitudinal axis A₁.

The surgical tool 200 may include, but is not limited to, forceps, agrasper, a needle driver, scissors, an electro cautery tool, a vesselsealer, a stapler, a clip applier, a hook, a spatula, a suction tool, anirrigation tool, an imaging device (e.g., an endoscope or ultrasonicprobe), or any combination thereof. In some embodiments, the surgicaltool 200 may be configured to apply energy to tissue, such as radiofrequency (RF) energy. In the illustrated embodiment, the end effector204 comprises a tissue grasper and vessel sealer that include opposingjaws 210, 212 configured to move (articulate) between open and closedpositions. As will be appreciated, however, the opposing jaws 210, 212may alternatively form part of other types of end effectors such as, butnot limited to, surgical scissors, a clip applier, a needle driver, ababcock including a pair of opposed grasping jaws, bipolar jaws (e.g.,bipolar Maryland grasper, forceps, a fenestrated grasper, etc.), etc.One or both of the jaws 210, 212 may be configured to pivot relative tothe other to open and close the jaws 210, 212. The principles of thepresent disclosure, however, are equally applicable to end effectorswithout opposing jaws.

FIG. 3 illustrates the potential degrees of freedom in which the wrist206 may be able to articulate (pivot). The wrist 206 comprises a jointconfigured to allow pivoting movement of the end effector 204 relativeto the shaft 202. The degrees of freedom of the wrist 206 arerepresented by three translational variables (i.e., surge, heave, andsway) and three rotational variables (i.e., Euler angles or roll, pitch,and yaw). The translational and rotational variables describe theposition and orientation of the end effector 204 with respect to a givenreference Cartesian frame. “Surge” refers to forward and backwardtranslational movement, “heave” refers to translational movement up anddown, and “sway” refers to translational movement left and right. “Roll”refers to tilting side to side, “pitch” refers to tilting forward andbackward, and “yaw” refers to turning left and right.

The pivoting motion can include pitch movement about a first axis of thewrist 206 (e.g., X-axis), yaw movement about a second axis of the wrist206 (e.g., Y-axis), and combinations thereof to allow for 360°rotational movement of the end effector 204 about the wrist 206. Inother applications, the pivoting motion can be limited to movement in asingle plane, e.g., only pitch movement about the first axis of thewrist 206 or only yaw movement about the second axis of the wrist 206,such that the end effector 204 moves only in a single plane.

Referring again to FIG. 2, the surgical tool 200 may also include aplurality of drive cables (obscured in FIG. 2) that form part of a cabledriven motion system that facilitates movement and articulation of theend effector 204 relative to the shaft 202. Moving (actuating) the drivecables moves the end effector 204 between an unarticulated position andan articulated position. The end effector 204 is depicted in FIG. 2 inthe unarticulated position where a longitudinal axis A₂ of the endeffector 204 is substantially aligned with the longitudinal axis A₁ ofthe shaft 202, such that the end effector 204 is at a substantially zeroangle relative to the shaft 202. In the articulated position, thelongitudinal axes A₁, A₂ would be angularly offset from each other suchthat the end effector 204 is at a non-zero angle relative to the shaft202.

In some embodiments, the surgical tool 200 may be supplied withelectrical power (current) via a power cable 214 coupled to the drivehousing 208. In other embodiments, the power cable 214 may be omittedand electrical power may be supplied to the surgical tool 200 via aninternal power source, such as one or more batteries or fuel cells. Insuch embodiments, the surgical tool 200 may alternatively becharacterized and otherwise referred to as an “electrosurgicalinstrument” capable of providing electrical energy to the end effector204. The power cable 214 may place the surgical tool 200 incommunication with a generator 216 that supplies energy, such aselectrical energy (e.g., radio frequency energy), ultrasonic energy,microwave energy, heat energy, or any combination thereof, to thesurgical tool 200 and, more particularly, to the end effector 204.

FIG. 4 is an enlarged isometric view of the distal end of the surgicaltool 200 of FIG. 2. More specifically, FIG. 4 depicts an enlarged viewof the end effector 204 and the wrist 206, with the jaws 210, 212 of theend effector 204 in the open position. The wrist 206 operatively couplesthe end effector 204 to the shaft 202. In some embodiments, however, ashaft adapter may be directly coupled to the wrist 206 and otherwiseinterpose the shaft 202 and the wrist 206. Accordingly, the wrist 206may be operatively coupled to the shaft 202 either through a directcoupling engagement where the wrist 206 is directly coupled to thedistal end of the shaft 202, or an indirect coupling engagement where ashaft adapter interposes the wrist 206 and the distal end of the shaft202. As used herein, the term “operatively couple” refers to a direct orindirect coupling engagement between two components.

To operatively couple the end effector 204 to the shaft 202, the wrist206 includes a first or “distal” linkage 402 a, a second or“intermediate” linkage 402 b, and a third or “proximal” linkage 402 c.The linkages 402 a-c facilitate articulation of the end effector 204relative to the elongate shaft 202. Articulation via the linkages 402a-c may be limited to pitch only, yaw only, or a combination thereof. Asillustrated, the distal end of the distal linkage 402 a may be coupledto the end effector 204 and, more particularly, to the lower jaw 212 (oran extension of the lower jaw 212). The proximal end of the distallinkage 402 a may be rotatably coupled to the intermediate linkage 402 bat a first axle 404 a, and the intermediate linkage 402 b may also berotatably coupled to the proximal linkage 402 c at a second axle 404 b.The proximal end of the proximal linkage 402 c may be coupled to adistal end 406 of the shaft 202 (or alternatively a shaft adapter).

A first pivot axis P₁ extends through the first axle 404 a and a secondpivot axis P₂ extends through the second axle 404 b. The first pivotaxis P₁is substantially perpendicular (orthogonal) to the longitudinalaxis A₂ of the end effector 204, and the second pivot axis P₂ issubstantially perpendicular (orthogonal) to both the longitudinal axisA₂ and the first pivot axis P₁. Movement about the first pivot axis P₁provides “yaw” articulation of the end effector 204, and movement aboutthe second pivot axis P₂ provides “pitch” articulation of the endeffector 204. Alternatively, the first pivot axis P₁ could be configuredto provide “pitch” articulation and the second pivot axis P₂ could beconfigured to provide “yaw” articulation.

A plurality of drive cables, shown as drive cables 408 a, 408 b, 408 c,and 408 d, extend longitudinally within a lumen 410 defined by the shaft202 (or a shaft adaptor) and pass through the wrist 206 to beoperatively coupled to the end effector 204. The drive cables 408 a-dform part of the cable driven motion system briefly described above, andmay be referred to and otherwise characterized as cables, bands, lines,cords, wires, woven wires, ropes, strings, twisted strings, elongatemembers, etc. The drive cables 408 a-d can be made from a variety ofmaterials including, but not limited to, metal (e.g., tungsten,stainless steel, etc.) a polymer (e.g., ultra-high molecular weightpolyethylene), a synthetic fiber (e.g., KEVLAR®, VECTRAN®, etc.), or anycombination thereof. While four drive cables 408 a-d are depicted inFIG. 4, more or less than four drive cables 408 a-d may be included,without departing from the scope of the disclosure.

The drive cables 408 a-d extend proximally from the end effector 204 tothe drive housing 208 (FIG. 2) where they are operatively coupled tovarious actuation mechanisms (e.g., capstans) or devices housed thereinto facilitate longitudinal movement (translation) of the drive cables408 a-d within the lumen 410. Selective actuation of the drive cables408 a-d causes corresponding drive cables 408 a-d to translatelongitudinally within the lumen 410 and thereby cause pivoting movement(articulation) of the end effector 204. Moving a given drive cable 408a-d applies tension (i.e., pull force) to the given drive cable 408 a-din a proximal direction, which causes the given drive cable 408 a-d totranslate and thereby cause the end effector 204 to move (articulate).

The drive cables 408 a-d each extend longitudinally through the first,second, and third linkages 402 a-c. In some embodiments, each linkage402 a-c may define four, equidistantly-spaced apertures 412 (only twolabeled) configured to guide the drive cables 408 a-d through the wrist206. The apertures 412 of each linkage 402 a-c coaxially align when theend effector 204 is in the unarticulated position.

The distal end of each drive cable 408 a-d may terminate at the distallinkage 402 a, thus operatively coupling each drive cable 408 a-d to theend effector 204 and, more particularly, to the lower jaw 212. Thedistal end of each drive cable 408 a-d may be enlarged to facilitatefixed attachment thereof to the end effector 204. In some embodiments,as illustrated, the distal end of each drive cable 408 a-d may include aball crimp 413 (only one shown).

The jaws 210, 212 may be moved between the closed and open positions bypivoting the upper jaw 210 relative to the lower jaw 212. In theillustrated embodiment, the upper jaw 210 may be rotatably coupled(mounted) to the lower jaw 212 at a jaw axle 414. A third pivot axis P₃extends through the jaw axle 414 and is generally perpendicular(orthogonal) to the first pivot axis P₁ and parallel to the second pivotaxis P₂. In this embodiment, the lower jaw 212 remains stationary as theupper jaw 210 pivots about the third pivot axis P₃.

A central pulley 416 (partially visible) may be mounted to the jaw axle414 and receive a jaw cable 418 that may be actuated to selectively openand close the jaws 210, 212. Similar to the drive cables 408 a-d, thejaw cable 418 extends longitudinally within the lumen 410 and passesthrough the wrist 206. The jaw cable 418 may form part of the cabledriven motion system described herein and, therefore, may extendproximally from the end effector 204 to the drive housing 208 (FIG. 2).The jaw cable 418 may comprise a single line or wire looped around thecentral pulley 416 and opposing first and second ends 420 a and 420 b ofthe jaw cable 418 extend proximally to the drive housing 208. Actuationof corresponding drive inputs will cooperatively cause tension or slackin the jaw cable 418 and thereby cause the upper jaw 210 to rotate aboutthe third pivot axis P₃ between the open and closed positions.

In some embodiments, an electrical conductor 422 may supply electricalenergy to the end effector 204 and, more particularly, to an electrode424 included in the end effector 204. The electrical conductor 422extends longitudinally within the lumen 410, through the wrist 206, andterminates at the electrode 424. In some embodiments, the electricalconductor 422 may comprise a wire, but may alternatively comprise arigid or semi-rigid shaft, rod, or strip (ribbon) made of a conductivematerial. The electrical conductor 422 may be partially covered with aninsulative covering (overmold) made of a non-conductive material. Usingthe electrical conductor 422 and the electrode 424, the end effector 204may be configured for monopolar or bipolar operation.

In the illustrated embodiment, the end effector 204 comprises acombination tissue grasper and vessel sealer that includes a cuttingelement 426 (mostly occluded), alternately referred to as a “knife” or“blade.” The cutting element 426 is aligned with and configured totraverse a guide track 428 defined longitudinally in one or both of theupper and lower jaws 210, 212. The cutting element 426 may beoperatively coupled to the distal end of a drive rod 430 that extendslongitudinally within the lumen 410 and passes through the wrist 206.Longitudinal movement (translation) of the drive rod 430 correspondinglymoves the cutting element 426 within the guide track(s) 428. Similar tothe drive and jaw cables 408 a-d, 418, the drive rod 430 may form partof the cable driven motion system and, therefore, may extend proximallyfrom the cutting element 426 to the drive housing 208 (FIG. 2).Selective actuation of a corresponding drive input will cause the driverod 430 to move distally or proximally within the lumen 410, andcorrespondingly move the cutting element 426 in the same direction.

FIG. 5 is an isometric side view of the end effector 204 in an openposition, according to one or more embodiments. More particularly, FIG.5 depicts the upper jaw 210 pivoted to the open position, and the lowerjaw 212 (FIG. 4) is omitted to enable viewing of the internal componentsof the end effector 204. As illustrated, the end effector 204 includes apivot link 502 operatively coupled to the upper jaw 210. Morespecifically, the upper jaw 210 provides or otherwise defines one ormore legs 504 (one shown, one occluded) that are pivotably coupled to acorresponding one or more legs 506 (one shown, one occluded) of thepivot link 502 at a pivot axle 508. A fourth pivot axis P₄ extendsthrough the pivot axle 508 and may be generally perpendicular(orthogonal) to the first pivot axis P₁ and parallel to the second andthird pivot axes P₂, P₃.

The central pulley 416 (mostly occluded) is rotatably supported on thejaw axle 414, and the jaw cable 418 loops around the central pulley 416and the opposing ends 420 a,b of the jaw cable 418 extend proximallythrough the wrist 206. The jaw cable 418 may be operatively coupled tothe pivot link 502 such that movement (i.e., longitudinal translation)of the jaw cable 418 correspondingly moves the pivot link 502. Forexample, a cable anchor 510 may be secured to or otherwise form part ofone proximally extending end 420 a,b of the jaw cable 418 and may helpoperatively couple the jaw cable 418 to the pivot link 502.

To move the jaws 210, 212 to the open position, the jaw cable 418 may beactuated to move the pivot link 502 distally, which may be done, forexample, by pulling proximally on the second end 420 b of the jaw cable418 (alternately referred to as the “open cable”). As the pivot link 502moves distally, the legs 506 of the pivot link 502 act on the legs 504of the upper jaw 210 at the pivot axle 508 and forces the legs 504downward in rotation about the fourth pivot axis P₄. Downward movementof the legs 504 correspondingly causes the upper jaw 210 to pivot aboutthe third pivot axis P₃. As it pivots about the third pivot axis P₃, theupper jaw 210 is moved to the open position.

To move the upper jaw 210 back to the closed position, the jaw cable 418may be actuated to move the pivot link 502 proximally, which may be doneby pulling proximally on the first end 420 a of the jaw cable 418(alternately referred to as the “closure cable”). This causes the pivotlink 502 to pull upward on the legs 504 of the upper jaw 210 in rotationabout the fourth pivot axis P₄, and upward movement of the legs 504correspondingly causes the upper jaw 210 to pivot about the third pivotaxis P₃ and moves the upper jaw 210 to the closed position.

FIGS. 6A and 6B are enlarged isometric front and back views,respectively, of the wrist 206, according to one or more embodiments.The wrist 206 has a first or “distal” end 602 a and a second or“proximal” end 602 b opposite the distal end 602 a. The distal linkage402 a is positioned at the distal end 602 a, the proximal linkage 402 cis positioned at the proximal end 602 b, and the intermediate linkage402 b interposes and operatively couples the distal and proximallinkages 402 a,c. However, embodiments are contemplated herein where theintermediate linkage 402 b is omitted and the distal and proximallinkages 402 a,c are alternatively directly coupled at a common axle.

For simplicity, the drive cables 408 a-d, the electrical conductor 422,the first and second ends 420 a,b of the jaw cable 418 (FIGS. 4 and 5),and the drive rod 430 are each depicted in FIGS. 6A-6B as dashed lines.The drive cables 408 a-d pass through portions (e.g., apertures 412) ofthe wrist 206 and terminate at the distal linkage 402 a. The proximallinkage 402 c may provide or otherwise define longitudinal grooves 604that accommodate each drive cable 408 a-d, and each groove 604 mayreceive a corresponding one of the drive cables 408 a-d. The grooves 604may be aligned with the corresponding apertures 412 defined by theproximal linkage 402 c.

The wrist 206 provides or defines a central channel 606 that extendsbetween the distal and proximal ends 602 a,b. In embodiments where thewrist 206 includes the distal, intermediate, and proximal linkages 402a-c, corresponding portions of the central channel 606 may becooperatively and successively defined by each linkage 402 a-c. However,in embodiments where the wrist 206 includes only the distal and proximallinkages 402 a,c, the central channel 606 may be defined cooperativelyand successively by only the distal and proximal linkages 402 a,c. Theportions of the central channel 606 defined by each linkage 402 a-c maycoaxially align when the wrist 206 is non-articulated, but may move outof axial alignment once the wrist 206 is moved in articulation.

The electrical conductor 422, the first and second ends 420 a,b of thejaw cable 418 (FIGS. 4 and 5), and the drive rod 430 may extend throughthe wrist 206 via the central channel 606. More particularly, the wrist206 may include a flexible member 608 positionable within the centralchannel 606 and extending at least partially between the first andsecond ends 602 a-b of the wrist 206. As best seen in FIG. 6B, theflexible member 608 may provide or otherwise define one or more conduits610 (four shown) that extend through the entire length of the flexiblemember 608. Consequently, the flexible member 608 may be referred to asa “multilumen element.” The conduits 610 may be configured to receivethe electrical conductor 422, the first and second ends 420 a,b of thejaw cable 418, and the drive rod 430, collectively referred to herein as“central actuation members.” Accordingly, the central actuation membersmay penetrate the wrist 206 by extending through the conduits 610 of theflexible member 608. In some embodiments, as illustrated, the conduits610 may exhibit a circular cross-sectional shape, but couldalternatively exhibit other cross-sectional shapes, such as polygonal,oval, or ovoid, without departing from the scope of the disclosure.Moreover, one or more of the conduits 610 may be lined with a material,such as nylon, silicone, nitinol, etc. Furthermore, the size (diameter)of the conduits 610 may vary, depending on the application. Thoseskilled in the art will readily appreciate that the shape, material, andsize of the conduits 610 may be altered or otherwise customizedconsistent with known industry practices, without departing from thescope of the disclosure.

The flexible member 608 may be operatively coupled to the distal linkage402 a at its distal end, but may be free to move axially relative to theproximal linkage 402 c at its proximal end. In some embodiments, forexample, the wrist 206 may include a distal adapter 612 (FIG. 6A) and aproximal adapter 614 (FIG. 6B). The distal adapter 612 may operativelycouple the flexible member 608 to the distal linkage 402 a, and theproximal adapter 612 may be configured to support the flexible member608 in sliding axial engagement with the proximal linkage 402 c. In atleast one embodiment, however, the proximal adapter 612 may be omittedand the flexible member 608 may directly contact the proximal linkage402 c in sliding engagement.

FIGS. 7A and 7B are isometric and exploded views, respectively, of theflexible member 608 and the distal and proximal adapters 612, 614,according to one or more embodiments. As illustrated, the flexiblemember 608 may comprise a generally cylindrical body 702 having a firstor “distal” end 704 a and a second or “proximal” end 704 b opposite thedistal end 704 a. In some embodiments, as illustrated, the body 702 mayexhibit a substantially circular cross-section, but may alternativelyexhibit other cross-sectional shapes, such as polygonal (e.g.,triangular, rectangular, etc.), oval, ovoid, or any combination thereof,without departing from the scope of the disclosure.

The flexible member 608 may be made of any flexible or semi-flexiblematerial that allows the flexible member 608 to flex or bend when thewrist 206 (FIGS. 6A-6B) articulates. The material for the flexiblemember 608 may also exhibit low friction characteristics or mayotherwise be lubricious, which may prove advantageous in minimizingfriction caused by the central actuation members (e.g., the electricalconductor 422, the first and second ends 420 a,b of the jaw cable 418,and the drive rod 430 of FIGS. 6A-6B) extending through the conduits610. Furthermore, the material for the flexible member 608 may alsoexhibit good wear characteristics so the central actuation members donot inadvertently cut through the corresponding conduits 610 followingrepeated use. The diameter or size of each conduit 610 may be largeenough to enable the central actuation members to move therein withoutsubstantive obstruction (friction), but small enough to support thecentral actuation members for longitudinal movement.

Suitable materials for the flexible member 608 include, but are notlimited to, polytetrafluoroethylene (PTFE or TEFLON®), silicone, nylon,a thermoplastic polyurethane (TPU, e.g., CARBOTHANE™, PELLETHAN®,TECOBAX™), a thermoplastic elastomer (TPE, e.g., PEBAX®), or anycombination thereof. In at least one embodiment, the flexible member 608may comprise an extrusion or may otherwise be manufactured through anextrusion process.

The distal adapter 612 may be made of a rigid or semi-rigid materialincluding, but not limited to, a plastic, a metal, a composite material,and any combination thereof. Example materials for the distal adapter612 include, but are not limited to, polyetherimide, polycarbonate,polystyrene, and nylon. In some embodiments, as illustrated, the distaladapter 612 may provide or otherwise define a radial shoulder 706 and aflange 708 that extends from the radial shoulder 706. The flange 708 maybe sized to receive the distal end 704 a of the flexible member 608. Inother embodiments, however, the flange 708 may be omitted and the distaladapter 612 may nonetheless be coupled to the flexible member 608.

The distal adapter 612 may be coupled (fixed) to the distal end 704 a ofthe flexible member 608 via a variety of attachment means. Suitableattachment means include, but are not limited to, bonding (e.g., anadhesive), welded (e.g., sonic or ultrasonic welding), overmolding thedistal adapter 612 onto the distal end 704 a, an interference or shrinkfit, or any combination thereof.

The distal adapter 612 may define one or more or apertures 710 (fourshown) configured to co-axially align with the conduits 610 of theflexible member 608. Accordingly, the central actuation membersextending through the flexible member 608 (e.g., the electricalconductor 422, the first and second ends 420 a,b of the jaw cable 418,and the drive rod 430 of FIGS. 6A-6B) may each exit the flexible member608 at the apertures 710 of the distal adapter 612.

In some embodiments, the distal adapter 612 may provide one or morefeatures 712 configured to mate with one or more corresponding featuresof the distal linkage 402 a (FIGS. 6A-6B). In the illustratedembodiment, the features 712 are defined on the flange 708, but couldalternatively be defined on any other portion of the distal adapter 612,without departing from the scope of the disclosure. Mating the features712 of the distal adapter 612 with the corresponding features of thedistal linkage 402 a may help rotationally fix the distal end 704 a ofthe flexible member 608 at the distal end 602 a (FIGS. 6A-6B) of thewrist 206 (FIGS. 6A-6B).

The proximal adapter 614 may be made of a rigid or semi-rigid materialincluding, but not limited to, a plastic, a metal, a composite material,or any combination thereof. Example materials for the proximal adapter614 include, but are not limited to, polyetherimide, polycarbonate,polystyrene, and nylon. The proximal adapter 614 may provide a generallyannular body 714 sized to receive the proximal end 704 b of the flexiblemember 608. In some embodiments, the proximal end 704 b may extendentirely through the annular body 714, but may alternatively extend onlypartially therethrough.

The proximal adapter 614 may be coupled (fixed) to the proximal end 704b of the flexible member 608 via a variety of attachment means. Suitableattachment means include, but are not limited to, bonding (e.g., anadhesive), welded (e.g., sonic or ultrasonic welding), overmolding theproximal adapter 614 onto the proximal end 704 b, an interference orshrink fit, or any combination thereof.

In some embodiments, a flange 716 may extend proximally from the body714 of the proximal adapter 614 and may provide or define a groove 718coaxially alignable with one of the conduits 610. The groove 718 may besized to receive one of the central actuation members, such as the driverod 430 (FIGS. 5 and 6A-6B), which may prove advantageous in helping toprevent buckling of the drive rod 430 during operation.

The proximal adapter 614 may provide one or more features 720 matablewith one or more corresponding features provided by the proximal linkage402 c (FIGS. 6A-6B). As discussed in more detail below, the feature 720may comprise a longitudinal rib that may be configured to mate with alongitudinal channel of the proximal linkage 402 c.

Referring again to FIGS. 6A-6B, in some embodiments, the distal adapter612 may be partially received within the central channel 606 defined inthe distal linkage 402 a. More specifically, the flange 708 (see FIG.6B) of the distal adapter 612 may extend into the central channel 606until the radial shoulder 706 (see FIG. 6A) of the distal adapter 612engages the distal end 602 a of the wrist 206 and, more particularly,the distal linkage 402 a. In some embodiments, one or more features (notshown) may be defined on the inner radial surface of the central channel606 at the distal linkage 402 a and configured to mate with the features712 (FIGS. 7A-7B) of the distal adapter 612. Mating these features mayhelp rotationally fix the distal adapter 612 relative to the distal end602 a (FIGS. 6A-6B) of the wrist 206 (FIGS. 6A-6B).

The distal adapter 612 may be arranged to interpose the lower jaw 212(FIG. 4) and the distal linkage 402 a within the assembly of the endeffector 204 (FIGS. 4-5), thus restraining (trapping) the distal adapter612 between the lower jaw 212 and the distal linkage 402 a. Since thedistal adapter 612 may be fixed to the distal end 704 a (FIGS. 7A-7B) ofthe flexible member 608, restraining (trapping) the distal adapter 612between the lower jaw 212 and the distal linkage 402 a maycorrespondingly fix the flexible member 608 in place at the distal end602 a of the wrist 206.

Referring specifically to FIG. 6B, the proximal linkage 402 c mayprovide or define a feature 618 sized and otherwise configured toreceive (mate with) the feature 720 provided by the proximal adapter614. In the illustrated embodiment, the feature 618 comprises alongitudinal channel, and the feature 720 comprises a longitudinal ribmatable with the longitudinal channel. Mating the features 618, 720 mayhelp rotationally fix the flexible member 608 to the proximal linkage402 c, but also allows the flexible member 608 to move longitudinallyrelative to the proximal linkage 402 c. For example, as the wrist 206articulates, the feature 720 of the proximal adapter 614 may sliderelative to the feature 618 of the proximal linkage 402 c. In someembodiments, however, the proximal adapter 614 may be omitted and thefeature 720 may alternatively be provided by the flexible member 608,without departing from the scope of the disclosure. In otherembodiments, the flexible member 608 may be molded or otherwise formedin a shape that lends itself to be rotationally fixed to the proximallinkage 402 c, such as a square or “D” shape.

In example operation of the wrist 206, the drive cables 408 a-d areselectively actuated to articulate the wrist 206. As the wrist 206articulates, the flexible member 608 correspondingly bends or flexes,and the central actuation members (e.g., the electrical conductor 422,the first and second ends 420 a,b of the jaw cable 418, and the driverod 430) will correspondingly move in the direction of articulation andthereby lengthen or shorten, depending on the bend direction. Extendingthe central actuation members through the conduits 610 of the flexiblemember 608 creates a defined and predictable pathway for each centralactuation member.

The wrist 206 is required to exhibit a stiffness sufficient to resistexternal loads and moments induced by actuation and clamping of the jaws210, 212 (FIGS. 2, 4, and 5). To maintain stiffness in the wrist 206 inboth static and dynamic conditions, the drive cables 408 a-d aretypically placed under pretension. However, maintaining accurate andconsistent joint stiffness in the wrist 206 using only pretension can bedifficult, and the pretension will eventually degrade over time due tocreep of the drive cables 408 a-d. According to the present disclosure,various embodiments and designs of the flexible member 608 may be usedto supplement the stiffness in the wrist 206 and thereby minimize therequired pretension and improve surgical tool performance.

FIGS. 8A and 8B are isometric and end views, respectively, of oneexample embodiment of the flexible member 608 in accordance with theprinciples of the present disclosure. As illustrated, the flexiblemember 608 comprises the body 702 having the distal and proximal ends704 a,b, and the one or more conduits 610 (four shown) extend throughbody 702 between the distal and proximal ends 704 a,b to accommodate thecentral actuation members (i.e., the electrical conductor 422, the firstand second ends 420 a,b of the jaw cable 418, and the drive rod 430 ofFIGS. 6A-6B). As mentioned above, each conduit 610 may accommodate acorresponding one of the central actuation members.

One or more stiffening members 802 (one shown), alternately referred toas “stringers,” may be contained within the body 702 to help increasethe stiffness of the flexible member 608, and thereby supplement thestiffness in the wrist 206 (FIGS. 6A-6B). In the illustrated embodiment,the flexible member 608 includes one stiffening member 802 arranged atthe center of the body 702 and extending coaxial with a central axis 804of the body 702. The stiffening member 802 may extend at least partiallybetween the distal and proximal ends 704 a,b. In some embodiments, asillustrated, the stiffening member 802 may extend entirely between thedistal and proximal ends 704 a,b.

In the illustrated embodiment, the stiffening member 802 comprises a rodor wire having a substantially circular cross-section. In otherembodiments, as discussed below, the stiffening member 802 may exhibitother cross-sectional shapes (e.g., polygonal), without departing fromthe scope of the disclosure. The stiffening member 802 may be made of avariety of rigid materials including, but not limited to, a plastic, ametal, a composite material, or any combination thereof. Examplematerials for the stiffening member 802 include, but are not limited to,nickel titanium (i.e., nitinol), stainless steel, graphite epoxy, nylon,polyetheretherketone (PEEK), a thermoplastic polyurethane (TPU, e.g.,CARBOTHANE™, PELLETHAN®, TECOBAX™), a thermoplastic elastomer (TPE,e.g., PEBAX®,), or any combination thereof. Example composite materialsinclude, but are not limited to, fiberglass, carbon fiber, afiber-reinforced matrix system, or any combination of any of these.

The stiffening member 802 may be included in the body 702 using variousmanufacturing processes. In some embodiments, for example, the body 702may define a channel 806 sized to receive the stiffening member 802. Inother embodiments, the body 702 may be molded onto or around thestiffening member 802. In yet other embodiments, the stiffening member802 may be co-molded or co-extruded with the body 702. In even furtherembodiments, the stiffening member 802 may be forced to penetrate thebody 702 at the desired location. In yet other embodiments, thestiffening member 802 may be adhesive bonded or manufactured via areflow mold process, where metallic elements are heated and theextrusion resin is allowed to melt locally and reflow around the metalas it cools.

The stiffening member 802 essentially acts as a cantilevered spring thatprovides predictable resistance to bending of the flexible member 608.More specifically, the stiffening member 802 embedded within theflexible member 608 acts like a cantilever beam, and will cause thedeflection resistance force of the flexible member 608 to increase asthe articulation angle or bending of the flexible member 608 increases.The resistance force (P) provided by the stiffening member 802 can bedetermined using a formula for a cantilever beam loaded at a free end:

$P = \frac{3{EI}\;\theta_{\max}}{L^{3}}$

where E is the modulus of elasticity of the stiffening member 802, I isthe moment of inertia of the cross-sectional area of the flexible member608 about the bending axis (i.e., the central axis 804), θ_(max) is thedeflection or articulation angle of the stiffening member 802 at thefree end of the stiffening member 802, and L is the length of thestiffening member 802.

As an example, the stiffening member 802 may have a diameter of 0.019inches, a length L of 0.375 inches, and, as illustrated, is arranged atthe center of the flexible member 608 (i.e., along the central axis804). When the stiffening member 802 is bent to an articulation angle θof 40°, the stiffening member 802 will provide a corresponding resistiveforce of 0.88 lbs. Accordingly, the stiffening member 802 may be able tosupplement the stiffness of the flexible member 608 with a resistiveforce of 0.88 lbs. when the flexible member 608 is bent to 40°.

FIGS. 9A and 9B are isometric and end views, respectively, of anotherexample embodiment of the flexible member 608 in accordance with theprinciples of the present disclosure. Similar to the embodiment of FIGS.8A-8B, one or more stiffening members 802 (four shown) may be containedwithin the body 702 to help increase the stiffness of the flexiblemember 608, and thereby supplement the stiffness in the wrist 206 (FIGS.6A-6B).

In the illustrated embodiment, the flexible member 608 provides orotherwise defines one or more lobes 902 (four shown) arranged about theouter periphery of the body 702 and extending between the distal andproximal ends 704 a,b. In at least one embodiment, the lobes 902 may beequidistantly spaced from each other, but this is not required. In theillustrated embodiment, each lobe 902 may be configured to contain orotherwise accommodate a corresponding one of the stiffening members 802.Accordingly, the stiffening members 802 of FIGS. 9A-9B may be arrangedeccentric to the central axis 804 of the flexible member 608, andotherwise located about a periphery of the body 702. In otherembodiments, as discussed below, the stiffening members 802 may beincluded within some but not all of the lobes 902, without departingfrom the scope of the disclosure.

In operation, each stiffening member 802 acts as a cantilevered springthat provides predictable resistance to the bending of the flexiblemember 608 in accordance with the formula provided above. Locating thestiffening members 802 away from the central axis 804 will dramaticallyincrease the moment of inertia (I) of the assembly, and the resultingstiffness of the flexible member 608. As an example, each stiffeningmember 802 may have a diameter of 0.019 inches and a length L of 0.375inches. When the stiffening member 802 is bent to an articulation angleθ of 40°, the four stiffening members 802 arranged eccentric to thecentral axis 804 will provide a corresponding resistive force of 307lbs. Accordingly, the stiffening members 802 may be able to supplementthe stiffness of the flexible member 608 with a resistive force of 307lbs. when the flexible member 608 is bent to 40°.

FIGS. 10A and 10B are isometric and end views, respectively, of anotherexample embodiment of the flexible member 608 in accordance with theprinciples of the present disclosure. Similar to the embodiments ofFIGS. 8A-8B and 9A-9B, the flexible member 608 may include one or morestiffening members 802 (three shown) to help increase the stiffness ofthe flexible member 608, and thereby supplement the stiffness in thewrist 206 (FIGS. 6A-6B). Moreover, similar to the embodiment of FIGS.9A-9B, the flexible member 608 includes the one or more lobes 902arranged about the outer periphery of the body 702 to potentiallyaccommodate one or more of the stiffening members 802.

In the illustrated embodiment, only two lobes 902 contain correspondingstiffening members 802, while a third stiffening member 802 is arrangedat the center of the body 702 and extending coaxial with the centralaxis 804. Unlike the embodiments of FIGS. 8A-8B and 9A-9B where thestiffening members 802 are used to augment stiffness of the flexiblemember 608 in all directions about the central axis 804, the stiffeningmembers 802 are selectively arranged in FIGS. 10A-10B to augment thestiffness of the flexible member 608 in a predetermined deflection(bending) direction.

In the present embodiment, for example, the arrangement of thestiffening members 802 may be configured to augment the stiffness of theflexible member 608 to counteract tip dive. More specifically, theclosure cable (i.e., the first end 420 a of the jaw cable 418 of FIG. 4)may extend through the top conduit 610 a, and the arrangement ofstiffening members 802 may provide passive stiffness to counteract thebending moment caused by actuation of the closure cable, which causesthe jaws 210, 212 (FIGS. 2, 4, and 5) to close. As tension in theclosure cable increases, the flexible member 608 may have a tendency tobend along a vertical plane 1002 extending through the central axis 804and the top conduit 610 a.

As an example, each stiffening member 802 may have a diameter of 0.010inches and a length L of 0.375 inches. When bent to an articulationangle θ of 40° along the vertical plane 1002, the three stiffeningmembers 802 arranged concentric and eccentric to the central axis 804 asdescribed above will cooperatively provide a corresponding resistiveforce of 106 lbs. Accordingly, the stiffening members 802 may be able tosupplement the stiffness of the flexible member 608 with a resistiveforce of 42.3 lbs. when the flexible member 608 is bent to 40°.

FIGS. 11A and 11B are isometric and end views, respectively, of anotherexample embodiment of the flexible member 608 in accordance with theprinciples of the present disclosure. Similar to the embodiments ofFIGS. 8A-8B, 9A-9B, and 10A-10B, one or more stiffening members, shownas a first stiffening member 1102 a and a second stiffening member 1102b, may be contained within the body 702 to help increase the stiffnessof the flexible member 608, and thereby supplement the stiffness in thewrist 206 (FIGS. 6A-6B). The stiffening members 1102 a,b may be made ofsimilar materials as the stiffening members 802 of FIGS. 8A-8B, 9A-9B,and 10A-10B.

Unlike the embodiments of FIGS. 8A-8B, 9A-9B, and 10A-10B, however, thestiffening members 1102 a,b may comprise bands or strips of materialthat exhibit a substantially polygonal cross-section. In the illustratedembodiment, each stiffening member 1102 a,b exhibits a rectangularcross-section having a height that is larger than its width. Moreover,the stiffening members 1102 a,b may be positioned in series andotherwise end-to-end along the central axis 804, where the firststiffening member 1102 a is arranged closer to the distal end 704 a andthe second stiffening member 1102 b is arranged closer to the proximalend 704 b. In other embodiments, however, the stiffening members 1102a,b may be arranged at other locations within the body 702.

In the illustrated embodiment, the first stiffening member 1102 a isoriented horizontally and otherwise along a horizontal plane 1104 aextending through the body 702, and the second stiffening member 1102 bis oriented vertically and otherwise along a vertical plane 1104 bextending through the body 702. In other embodiments, the orientation ofthe first and second stiffening members 1102 a,b may be reversed. Havingthe polygonal-shaped stiffening members 1102 a,b oriented differentlyalong the central axis 804 may selectively change the stiffness of theflexible member 608 along its axial length between the distal andproximal ends 704 a,b. More particularly, the horizontally-orientedfirst stiffening member 1102 a may augment the stiffness of the flexiblemember 608 at or near the distal end 704 a to help resist yaw movementof the flexible member 608. In contrast, the vertically-oriented secondstiffening member 1102 b may augment the stiffness of the flexiblemember 608 at or near the proximal end 704 b to help resist pitchmovement of the flexible member 608. Accordingly, the stiffness andflexibility of the flexible member 608 may be selectively limitedthrough predetermined placement of the polygonal-shaped stiffeningmembers 1102 a,b. Moreover, through predetermined placement of thepolygonal-shaped stiffening members 1102 a,b the stiffness in one planeof articulation may be different than the stiffness in a second plane ofarticulation.

Embodiments disclosed herein include:

A. An articulable wrist for an end effector that includes a distallinkage provided at a distal end of the articulable wrist, a proximallinkage provided at a proximal end of the articulable wrist, a centralchannel cooperatively defined by the distal and proximal linkages andextending between the distal and proximal ends, a flexible memberarranged within the central channel, and one or more stiffening membersarranged within the flexible member and extending at least partiallybetween the first and second ends, wherein the one or more stiffeningmembers increase a stiffness of the flexible member and the articulablewrist against bending.

B. A surgical tool that includes a drive housing, an elongate shaft thatextends from the drive housing, an end effector arranged at an end ofthe elongate shaft, an articulable wrist that interposes the endeffector and the elongate shaft, the articulable wrist including adistal linkage provided at a distal end of the articulable wrist, aproximal linkage provided at a proximal end of the articulable wrist, acentral channel cooperatively defined by the distal and proximallinkages and extending between the distal and proximal ends, a flexiblemember arranged within the central channel, and one or more stiffeningmembers arranged within the flexible member and extending at leastpartially between the first and second ends. The surgical tool furtherincluding one or more central actuation members extending from the drivehousing and through the flexible member via one or more conduits definedin the flexible member.

C. A method of operating a surgical tool includes positioning thesurgical tool adjacent a patient for operation, the surgical toolincluding a drive housing, an elongate shaft that extends from the drivehousing, an end effector arranged at an end of the elongate shaft, and awrist that interposes the end effector and the elongate shaft andincludes a distal linkage provided at a distal end of the articulablewrist, a proximal linkage provided at a proximal end of the articulablewrist, a central channel cooperatively defined by the distal andproximal linkages and extending between the distal and proximal ends, aflexible member arranged within the central channel, and one or morestiffening members arranged within the flexible member and extending atleast partially between the first and second ends. The method furtherincludes articulating the wrist and simultaneously bending the flexiblemember within the central channel, and resisting bending of the flexiblemember and the wrist with the one or more stiffening members.

Each of embodiments A, B, and C may have one or more of the followingadditional elements in any combination: Element 1: further comprisingone or more conduits defined in the flexible member to receive one ormore central actuation members extending through the flexible member.Element 2: wherein the flexible member exhibits a circular, multi-lobed,or polygonal cross-sectional shape. Element 3: wherein the one or morestiffening members are made of a material selected from the groupconsisting of nickel, titanium, stainless steel, graphite epoxy, acomposite material, nylon, polyetheretherketone, a thermoplasticpolyurethane, a thermoplastic elastomer, and any combination thereof.Element 4: wherein at least one of the one or more stiffening membersextends along a central axis of the flexible member. Element 5: whereinat least one of the one or more stiffening members is positioned offsetfrom a central axis of the flexible member. Element 6: wherein the oneor more stiffening members are selectively arranged to augment astiffness of the flexible member in a predetermined deflectiondirection. Element 7: wherein the one or more stiffening members exhibita circular or polygonal cross-section. Element 8: wherein at least oneof the one or more stiffening members exhibits a rectangularcross-section having a height that is larger than a width. Element 9:wherein two of the one or more stiffening members exhibit therectangular cross-section and are coaxially aligned along a central axisof the flexible member. Element 10: wherein a first of the two of theone or more stiffening members is oriented along a horizontal plane anda second of the two of the one or more stiffening members is orientedalong a vertical plane. Element 11: wherein the flexible member providesone or more lobes arranged about a periphery of the flexible member andat least one of the one or more stiffening members is positioned withina corresponding one of the one or more lobes. Element 12: whereinanother one of the one or more stiffening members extends along acentral axis of the flexible member. Element 13: wherein the one or morestiffening members are arranged such that a stiffness of the flexiblemember in a first plane of articulation is different than a stiffness ofthe flexible member in a second plane of articulation. Element 14:wherein the one or more stiffening members are manufactured via aprocess selected from the group consisting of overmolding, adhesivebonding, reflow molding, co-extrusion, and any combination thereof.

Element 15: wherein the flexible member exhibits a circular,multi-lobed, or polygonal cross-sectional shape. Element 16: wherein atleast one of the one or more stiffening members extends along a centralaxis of the flexible member. Element 17: wherein at least one of the oneor more stiffening members is positioned offset from a central axis ofthe flexible member. Element 18: wherein the one or more stiffeningmembers exhibit a circular or polygonal cross-section. Element 19:wherein the one or more stiffening members are arranged such that astiffness of the flexible member in a first plane of articulation isdifferent than a stiffness of the flexible member in a second plane ofarticulation.

By way of non-limiting example, exemplary combinations applicable to A,B, and C include: Element 7 with Element 8; Element 8 with Element 9;Element 9 with Element 10; Element 11 with Element 12; Element 15 withElement 16; Element 15 with Element 17; Element 15 with Element 18;Element 15 with Element 19; Element 18 with Element 16; Element 18 withElement 17; and Element 18 with Element 19.

Therefore, the disclosed systems and methods are well adapted to attainthe ends and advantages mentioned as well as those that are inherenttherein. The particular embodiments disclosed above are illustrativeonly, as the teachings of the present disclosure may be modified andpracticed in different but equivalent manners apparent to those skilledin the art having the benefit of the teachings herein. Furthermore, nolimitations are intended to the details of construction or design hereinshown, other than as described in the claims below. It is thereforeevident that the particular illustrative embodiments disclosed above maybe altered, combined, or modified and all such variations are consideredwithin the scope of the present disclosure. The systems and methodsillustratively disclosed herein may suitably be practiced in the absenceof any element that is not specifically disclosed herein and/or anyoptional element disclosed herein. While compositions and methods aredescribed in terms of “comprising,” “containing,” or “including” variouscomponents or steps, the compositions and methods can also “consistessentially of” or “consist of” the various components and steps. Allnumbers and ranges disclosed above may vary by some amount. Whenever anumerical range with a lower limit and an upper limit is disclosed, anynumber and any included range falling within the range is specificallydisclosed. In particular, every range of values (of the form, “fromabout a to about b,” or, equivalently, “from approximately a to b,” or,equivalently, “from approximately a-b”) disclosed herein is to beunderstood to set forth every number and range encompassed within thebroader range of values. Also, the terms in the claims have their plain,ordinary meaning unless otherwise explicitly and clearly defined by thepatentee. Moreover, the indefinite articles “a” or “an,” as used in theclaims, are defined herein to mean one or more than one of the elementsthat it introduces. If there is any conflict in the usages of a word orterm in this specification and one or more patent or other documentsthat may be incorporated herein by reference, the definitions that areconsistent with this specification should be adopted.

As used herein, the phrase “at least one of” preceding a series ofitems, with the terms “and” or “or” to separate any of the items,modifies the list as a whole, rather than each member of the list (i.e.,each item). The phrase “at least one of” allows a meaning that includesat least one of any one of the items, and/or at least one of anycombination of the items, and/or at least one of each of the items. Byway of example, the phrases “at least one of A, B, and C” or “at leastone of A, B, or C” each refer to only A, only B, or only C; anycombination of A, B, and C; and/or at least one of each of A, B, and C.

What is claimed is:
 1. An articulable wrist for an end effector, comprising: a distal linkage provided at a distal end of the articulable wrist; a proximal linkage provided at a proximal end of the articulable wrist; a central channel cooperatively defined at least in part by the distal and proximal linkages and extending between the distal and proximal ends; a flexible member arranged within the central channel and providing one or more lobes arranged about a periphery of the flexible member; and one or more stiffening members arranged within the flexible member and extending at least partially between the distal and proximal ends, wherein at least one of the one or more stiffening members is positioned within a corresponding one of the one or more lobes.
 2. The articulable wrist of claim 1, wherein at least one of the one or more stiffening members extends along a central axis of the flexible member.
 3. The articulable wrist of claim 1, wherein the one or more stiffening members are selectively positioned to augment a stiffness of the flexible member in a predetermined deflection direction.
 4. The articulable wrist of claim 1, wherein the one or more stiffening members are arranged such that a stiffness of the flexible member in a first plane of articulation is different than a stiffness of the flexible member in a second plane of articulation.
 5. The articulable wrist of claim 1, further comprising one or more conduits defined in the flexible member to receive one or more central actuation members extending through the flexible member.
 6. The articulable wrist of claim 1, further comprising an intermediate linkage interposing the distal and proximal linkages.
 7. A multilumen element for stiffening an articulable wrist of a surgical tool end effector, the multilumen element comprising: a body having first end and a second end opposite the first end, the body defining one or more lobes about a periphery of the body; and one or more stiffening members arranged within the body and extending at least partially between the first and second ends, wherein at least one of the one or more stiffening members is positioned within a corresponding one of the one or more lobes.
 8. The multilumen element of claim 7, wherein the body exhibits a circular cross-sectional shape.
 9. The multilumen element of claim 7, wherein the one or more stiffening members exhibit a circular or polygonal cross-section.
 10. The multilumen element of claim 7, further comprising one or more conduits defined in the body and extending between the first and second ends.
 11. The multilumen element of claim 7, wherein at least one of the one or more stiffening members extends along a central axis of the body.
 12. The multilumen element of claim 7, wherein the one or more stiffening members are arranged such that a stiffness of the body in a first plane of articulation is different than a stiffness of the body in a second plane of articulation.
 13. The multilumen element of claim 7, wherein the one or more stiffening members are made of a material selected from the group consisting of nickel, titanium, stainless steel, graphite epoxy, a composite material, nylon, polyetheretherketone, a thermoplastic polyurethane, a thermoplastic elastomer, and any combination thereof.
 14. The multilumen element of claim 7, wherein the one or more stiffening members are manufactured via a process selected from the group consisting of overmolding, adhesive bonding, reflow molding, co-extrusion, and any combination thereof.
 15. An articulable wrist for an end effector, comprising: a distal linkage provided at a distal end of the articulable wrist; a proximal linkage provided at a proximal end of the articulable wrist; a central channel cooperatively defined by the distal and proximal linkages and extending between the distal and proximal ends; a flexible member arranged within the central channel; and one or more stiffening members arranged within the flexible member and extending at least partially between the distal and proximal ends, wherein the one or more stiffening members include first and second stiffening members each exhibiting a rectangular cross-section, and wherein the first stiffening member is oriented along a horizontal plane and the second stiffening member is oriented along a vertical plane.
 16. The articulable wrist of claim 15, wherein the first and second stiffening members each exhibit a rectangular cross-section having a height that is larger than a width.
 17. The articulable wrist of claim 15, wherein the first and second stiffening members are coaxially aligned along a central axis of the flexible member.
 18. The articulable wrist of claim 15, wherein at least one of the one or more stiffening members is positioned eccentric to a central axis of the flexible member.
 19. The articulable wrist of claim 15, further comprising one or more conduits defined in the flexible member to receive one or more central actuation members extending through the flexible member.
 20. The articulable wrist of claim 15, further comprising an intermediate linkage interposing the distal and proximal linkages. 